Razor blades are typically formed of a suitable metallic sheet material such as stainless steel, which is slit to a desired width and heat-treated to harden the metal. The hardening operation utilizes a high temperature furnace, where the metal may be exposed to temperatures greater than 1145° C. for up to about 20 seconds, followed by quenching, whereby the metal is rapidly cooled to obtain certain desired material properties.
After hardening, a cutting edge is formed on the blade. The cutting edge typically has a wedge-shaped configuration with an ultimate tip having a radius less than about 1000 angstroms, e.g., about 200-300 angstroms. However, blade edge radii can range from 300 angstroms to 10,000 angstroms due to inherent limitations in the manufacture process using metallic sheet material.
The advantage of this prior method is that it is a proven, economical process for making blades in high volume at high speed. However, it is ever desirable to find processes that can further reduce edge quality variability in order to achieve improved sharpness consistency, and can form blade edges of increased strength that will result in a lower force required to trim hair, thereby improving comfort during shaving. It would be particularly desirable if such a process could utilize lower cost materials for blade formation.
Therefore, there is a need for a lower cost method of making blades for shaving razors having increased edge strength and less variability in edge sharpness to provide an improved shaving experience.